Centrifuge apparatus for processing blood

ABSTRACT

A centrifuge apparatus for processing blood comprising a bottom spring-loaded support plate; a top support plate; an axial inlet/outlet for blood to be processed and processed components of the blood, the axial inlet/outlet being attached to the top support plate by a rotating seal assembly; a variable volume separation chamber mounted between the bottom support plate and the top support plate, the variable volume separation chamber being fluidly connected to the axial inlet/outlet; a pump fluidly connected to the axial inlet/outlet; and a rotary drive unit attached to the bottom support plate. The top support plate is fixed vertically and the bottom spring-loaded support plate is mounted on springs that maintain pressure on the variable volume separation chamber and allow the bottom support plate to move vertically.

FIELD OF THE INVENTION

This invention relates to an apparatus for separating components ofwhole blood. More particularly, this invention relates to an apparatusfor the separation and collection of platelet poor plasma (PPP),platelet rich plasma (PRP), and red blood cells (RBC).

BACKGROUND OF THE INVENTION

Whole blood can be collected from a donor and processed into differentproducts. The collection and separation of blood typically has involvedmany steps as well as operator interaction.

Whole blood contains red blood cells, white blood cells, platelets, andplasma. Traditionally, these components were separated by a batchprocess in which a blood bag was spun for a period of approximately 10minutes in a large refrigerated centrifuge. After centrifugation, themain blood constituents, red blood cells (erythrocytes), platelets andwhite blood cells (leukocytes), and plasma sedimented and formeddistinct layers. These constituents were then expressed sequentially bya manual extractor in different satellite bags attached to the primarybag.

More recently, automated extractors have been introduced. Nevertheless,the whole process remains laborious. There remains a widespread need foran apparatus that will automatically separate the different componentsof whole blood efficiently and easily.

SUMMARY OF THE INVENTION

The invention provides a centrifuge apparatus for processing bloodcomprising a bottom spring-loaded support plate; a top support plate; anaxial inlet/outlet for blood to be processed and processed components ofthe blood, the axial inlet/outlet being attached to the top supportplate by a rotating seal assembly; a variable volume separation chambermounted between the bottom support plate and the top support plate, thevariable volume separation chamber being fluidly connected to the axialinlet/outlet; a pump fluidly connected to the axial inlet/outlet; and arotary drive unit attached to the bottom support plate. The top supportplate is fixed vertically and the bottom spring-loaded support plate ismounted on springs that maintain pressure on the variable volumeseparation chamber and allow the bottom support plate to movevertically.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an apparatus of this invention.

FIGS. 2A and 2B are cross-sectional views of the centrifuge and FIG. 2Cis a cross-sectional view of an alternate centrifuge.

FIGS. 3A to 3C are cross sectional views of the rotating seal of thecentrifuge.

FIGS. 4A to 4C are top, perspective and side views, respectively, ofrigid support plate used in the centrifuge of FIGS. 2 and 3 and FIG. 4Dis an exploded view of the top support plate, port, and rotating sealassembly.

FIG. 5A is a perspective view and FIG. 5B is a side view of thecartridge that contains the fluid sensor and the valve assembly.

FIG. 6A is a side view and FIGS. 6B and 6C are cross-sectional views ofthe fluid sensor pathway.

FIGS. 7A and 7B are cross-sectional and side views, respectively, of thevalve assembly when whole blood is flowing into the centrifuge.

FIGS. 8A and 8B are cross-sectional and side views, respectively, of thevalve assembly when PPP is flowing out of the centrifuge.

FIGS. 9A and 9B are cross-sectional and side views, respectively, of thevalve assembly when platelet rich plasma is flowing out of thecentrifuge.

FIGS. 10A and 10B are cross-sectional and side views, respectively, ofthe valve assembly when RBC and air are flowing out of the centrifugeand into the RBC compartment of the reservoir.

FIGS. 11A and 11B are cross-sectional and side views, respectively, ofthe valve core.

FIG. 12 is a cut-away partial detail view of the housing of theapparatus with the 4-way valve cartridge attached.

FIG. 13 is a partial cross-sectional view of the cartridge snapped onthe housing.

FIG. 14 is a side view of the multicomponent 3-compartment reservoirbag.

FIG. 15 is a perspective view of an alternate embodiment of theapparatus of this invention.

FIGS. 16A and 16B are perspective views of a pinch valve.

FIG. 17 is a perspective view of the disposable component of theapparatus of FIG. 15.

FIG. 18 is a perspective view of a flexible disk bag mounted in acentrifuge between the top plate and the bottom plate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In one embodiment, the invention provides an apparatus comprising acentrifuge with spring-loaded plate and top locking feature, a valvedriver mechanism, fluid sensor, peristaltic pump and touch screencomputer interface. Additionally, a syringe chiller may be provided tokeep various components in a syringe at a desired temperature.

In a preferred embodiment, a single use, sterile disposable processingset interfaces with the apparatus. The sterile disposable consists of acircular variable volume separation chamber with axial rotating sealassembly, 4-way valve cartridge with integral sensor and fluid pump loopand a pre-attached three compartment reservoir bag. Thethree-compartment reservoir bag consists of a chamber for anticoagulatedwhole blood, a chamber for platelet poor plasma, and a chamber forconcentrated red blood cells. Platelet rich plasma is collected in asterile syringe attached to the 4-way valve luer lock port.

Specifically, the invention provides a centrifuge apparatus forprocessing anticoagulated whole blood comprising a bottom spring-loadedsupport plate, a slotted top locking feature, and a stator arm assembly.The disposable variable volume separation chamber with rigid supportplate loads and locks into the spring loaded centrifuge chamber. Therotating seal of the separation chamber is interfaced and heldstationary by the stator arm assembly. Tubing is attached to therotating seal assembly to provide an axial inlet/outlet for blood to beprocessed and processed components of the blood. The 4-way valveassembly is attached to the inlet/outlet tube of the variable volumeseparation chamber. The 4-way valve is mounted to the fluid sensor andsnaps to the top housing of the apparatus. Rotation of the peristalticpump loads the fluid pump loop. The three compartment bag is attached toside of the apparatus to allow access to fluid inlet and outlet ports.

In a preferred embodiment, this invention achieves separation of wholeblood components according to the following method of operation. Thedisposable processing set is attached to the apparatus. Whole bloodcollected from the donor is mixed with anticoagulant and delivered tothe inlet port of the reservoir bag whole blood compartment. Theclinician selects the desired whole blood volume to process on the userinterface. The start button is selected to initiate the separation cycleand rotation of the centrifuge. The valve driver positions the 4-wayvalve to the whole blood compartment and the peristaltic pump drivesfluid from the reservoir to the spinning variable volume separationchamber. Fluid pressure inside the rotating separation chamber increaseswith increased gravitational force and the addition of whole blood. Thispressure drives the spring load bottom plate downward allowingadditional volume to enter the rotating system. The flexible variablevolume separation chamber changes shape and this shape change is limitedby a fixed stop internal to the centrifuge housing. Once adequateseparation of the whole blood components occurs, the centrifuge rotationspeed is decreased. The peristaltic pump direction is reversed, pumpingthe component layers from the axial port of the separation chamber. Theapparatus fluid sensor detects the concentration of the variouscomponent layers and utilizes algorithms to change the 4-way valveposition to the desired component layer collection vessel. The processis complete when all component layers are collected and the apparatusfluid sensor senses air. The 4-way valve fluid path allows the draw backof platelet poor plasma from the PPP reservoir compartment into the PRPsyringe. Multiple whole blood separation cycles are possible with thisinvention.

The advantages of this invention include the use of an automated systemand the ability to separate variable quantities of blood. Even verysmall quantities of whole blood can be efficiently separated, collected,and returned to a patient using the apparatus of this invention. Largervolumes can also be selected and processed within approximately the samecycle time of smaller volumes, allowing the clinician to harvest alarger quantity of platelets per cycle. This is advantageous in patientswith low platelet counts where more whole blood can be collected andprocessed in approximately the same cycle time with less dilution of thePRP product to produce substantially higher baseline multiples.

Additional advantages include the use of the fluid sensor to produce aPRP and PPP product void of red blood cells. The first component layerremoved from this apparatus after centrifugation is the PPP layer. Thefluid sensor detects when the PPP product is clear and free of red cellsprior to collection. The same is true for the PRP collection. Onceplatelets are sensed the platelet collection process is initiated andcontinues until red blood cells are sensed. The user can predeterminethe concentration of red blood cells in the final PRP product. This isadvantageous in certain clinical procedures.

The invention provides a centrifuge apparatus for processing bloodcomprising a bottom spring-loaded support plate; a top support plate; anaxial inlet/outlet for blood to be processed and processed components ofthe blood, the axial inlet/outlet being attached to the top supportplate by a rotating seal assembly; a variable volume separation chambermounted between the bottom support plate and the top support plate, thevariable volume separation chamber being fluidly connected to the axialinlet/outlet; a pump fluidly connected to the axial inlet/outlet; and arotary drive unit attached to the bottom support plate. The top supportplate is fixed vertically and the bottom spring-loaded support plate ismounted on springs that maintain pressure on the variable volumeseparation chamber and allow the bottom support plate to movevertically.

The invention provides a method of processing blood comprising:providing a centrifuge apparatus as described above; introducing aquantity of blood into the variable volume separation chamber;centrifuging the blood; and removing the separated components of theblood through the axial inlet/outlet.

The invention also provides a centrifuge apparatus for processing bloodcomprising a bottom support plate; a top support plate; an axialinlet/outlet for blood to be processed and processed components of theblood, the axial inlet/outlet being attached to the top support plate bya rotating seal assembly; a variable volume separation chamber mountedbetween the bottom support plate and the top support plate, the variablevolume separation chamber being fluidly connected to the axialinlet/outlet; a pump fluidly connected to the axial inlet/outlet; and arotary drive unit attached to the bottom support plate. The top holderis fixed vertically and the bottom support plate is mounted on aball-screw actuator that maintains pressure on the variable volumeseparation chamber and allows the bottom support plate to movevertically.

The invention provides a disposable cartridge comprising a plurality ofports for receiving or dispensing blood or blood components and a fluidsensor pathway for displaying blood or blood components for analysis,the cartridge being adapted to be mounted on a multi-position valve fordirecting flow between the ports and the fluid sensor pathway beingadapted to be mounted adjacent to one or more sensors for analyzingblood.

The invention provides a disposable set comprising: a container forblood; a plurality of containers for receiving separated components ofthe blood; a disk-shaped bag; a top support plate for a centrifuge; anaxial inlet/outlet for blood to be processed and processed components ofthe blood, the axial inlet/outlet being attached to the top supportplate by a rotating seal assembly; and tubing. The disposable set mayfurther comprise a disposable cartridge comprising a plurality of portsfor receiving or dispensing blood or blood components and a fluid sensorpathway for displaying blood or blood components for analysis, thecartridge being adapted to be mounted on a multi-position valve fordirecting flow between the ports and the fluid sensor pathway beingadapted to be mounted adjacent to one or more sensors for analyzingblood.

The blood component separation apparatus, as shown and described in theFigures, includes housing 10 containing centrifuge 20 (shown in crosssection in FIGS. 2A and 2B). With reference to FIG. 1, the apparatusincludes a user interface that comprises touch screen display 30. Asingle power supply is used for the centrifuge motor and for theelectronics. The apparatus also includes a fluid sensor 60, 4-way valve70, and 3-compartment reservoir/collection bag 90. The fluid sensorpathway 60 and the 4-way valve 70 are contained within cartridge 80,which in a preferred embodiment has a snap-on feature so that it isreadily removable and maintains its position on the apparatus duringuse. Blood and its components flow to and from the 3-compartmentreservoir/collection bag by means of flexible tubing. A syringe chiller85 may be provided to keep various fluids in a syringe at a desiredtemperature. For example, a Peltier device can be used to cool or heatthe syringe.

Blood is withdrawn from a patient, mixed with an appropriateanticoagulant (ACD-A, CPD-A) and placed in compartment 906 of the3-compartment reservoir/collection bag 90, as illustrated in FIG. 1. Thebag is connected via tubing line 416 to the 4-way valve core 71contained within the disposable cartridge 80 (FIGS. 11A and 11B). Thedisposable cartridge includes a tubing loop 411, which is configured tofit within the raceway of the peristaltic pump 40 contained on the topsurface of the housing. One end of the tubing connects to an inlet of aflexible and variable volume separation chamber. The blood is pumpedinto the centrifuge, where, in the flexible separation chamber, it isseparated into concentrated red blood cells (RBC), platelet poor plasma(PPP) and platelet rich plasma (PRP). These components are thentransferred out of the flexible separation chamber via tubing lines 410and 411. The RBC component is transferred to compartment 904 via tubingline 414, and PPP flows into compartment 902 via tubing line 412. Theplatelet rich plasma (PRP) flows into a syringe via port 802 (syringenot seen in FIG. 1).

The flexible variable volume separation chamber 140 and top supportplate 114 fits within the spring loaded plate 110 and top 111, havinglocking feature 112, on the centrifuge assembly 20. A stator armassembly 113 engages rotating seal 120. A spring-loaded support plate110 presses upward against the variable volume separation chamber 140though it is to be understood that the chamber and holder could beconfigured so that movement of the plate could be in any desireddirection. Motion of the plate, rotation of the peristaltic pump,specified whole blood volume and reduced rotational speed causesexpulsion of blood components. These components can exit the port 124coincident with the axis of the rotating seal assembly 120. A lid 115covers the centrifuge.

The valve system coupled with optical sensors permits the automation ofthis process. The graphical user interface (GUI) is object oriented anduses a unified modeling language. The apparatus thus can be used byoperators who have varying levels of sophistication.

Centrifuge

In operation, whole blood from the 3-compartment reservoir 90,specifically compartment 906 is pumped through the valve into a variablevolume separation chamber 140. The centrifuge is then rotated toseparate the blood components. The heavier components migrate to theouter portions of the separation chamber while the lighter componentsremain near the center of the separation chamber. Centrifuge 20 is shownin cross section in FIGS. 2A and 2B.

Motor 102 is operably connected to hollow shaft 104 which is integrallyformed with or mounted on spring-loaded support plate 110. Coil springs106 comprise one or more springs fit onto shafts 107 and are operablyconnected to support plate 110. Rotating seal assembly 120 includes port124. In FIG. 3B, lip-seals 301 attached to center hub 300 seal against astationary disk 302 which forms a fluid seal. Port 124 provides apassageway to the variable volume separation chamber 140, which is heldin the space between rigid support plate 114 and spring loaded plate110. Motor 102 rotates spring loaded plate 110, rigid support plate 114,and variable volume separation chamber 140.

During centrifugation, lower density blood components accumulate in thecenter region 145 of separation chamber 140, that is, close to the axisof rotation, while higher density components are urged toward theoutermost region. The bottom support plate 110 moves down to accommodatethe blood components due to centrifugal force.

For example, once whole blood has filled the separation chamber in thecentrifuge, the centrifuge is run for 7 minutes at 4000 rpm. Then therotation of the centrifuge motor is decreased. Decreasing the speed ofthe centrifuge causes reduced pressure inside the bag, allowing thespring-loaded support plate 110 to move upward against flexiblereservoir 140, causing its contents to be expelled via port 124. This,along with operation of peristaltic pump 40 in a direction reverse tothat during which the variable volume separation chamber was filled,causes expulsion of the blood components through the fluid exit portcoincident with the axis of the centrifuge (i.e., port 124).

Because PPP is less dense, it is expelled first. The PPP is directedthrough tubing 410 to the valve system, and fed into the PPP compartmentof the 3-chamber reservoir bag., as described below for FIGS. 7 to 10.Other components follow in sequence, also as described further below.

FIG. 2C illustrates an alternate embodiment of the centrifuge, and showscentrifuge 20b in a cross-sectional view wherein ball-screw actuator 206is used to control the space between the top holder and the bottomplate. The ball-screw actuator 206 as an example is automaticallycontrolled to maintain the desired space between the top holder 114 andthe bottom plate 110. It is possible to use other mechanical means suchas pneumatic, hydraulic or other mechanical actuators to achieve desiredpositioning of the bottom plate. Use of a pump to move fluids could beeliminated with a mechanical actuator. Such an actuated bottom platecould draw fluids in and expel fluids from the separation chamber.

Typically the apparatus of this alternate embodiment invention will beused by placing whole blood in the 3-chamber reservoir bag andtransferring it from there to the centrifuge. However, it is possible tocollect blood directly from the patient in the flexible disk bag of thecentrifuge. The flexible disk bag is the preferred embodiment of thevariable volume separation chamber. Since it is necessary to mix thecollected blood with an anti-coagulant, it is important to know theamount of blood being processed. The flexible disk bag is mounted in thecentrifuge between the top plate and the bottom plate. The distancebetween the top plate and the bottom plate correlates to a known volumeof blood in the flexible disk bag as shown by a graduated scale 117(shown in FIG. 18), which the user can visually inspect to determine theamount of blood entering the flexible reservoir. The operator thus canmonitor the amount of anti-coagulant and whole blood collected withoutthe use of a separate scale.

FIGS. 3A to 3C show various embodiments of a rotating seal. The rotatingseal shown in FIG. 3A is equivalent to the one shown in FIG. 3B. Theonly difference in the designs is the presence of two bearings 303 inFIG. 3A versus one bearing in FIG. 3B. Two bearings provide greaterstability of rotating components. FIGS. 3A and 3B both have a center hub300 that is attached to the center axis of the separation chamber 140.Bearing 303 is press fit onto the shaft of the center hub 300. Flexiblelip-seals 301 are attached to the center hub 300 and create a fluid sealwith a stationary sealing disk 302. Disk 302 is centered and sealed by acompressible gasket 304 that also provides a pre-load to the outer raceof the bearing 303 when compressed. The lower housing 305 providesfeatures that contain the above mentioned components. Top housing 306 isattached to the lower housing 305 and compresses and seals the internalcomponents of the rotating seal. Prior to assembly the center tube 307is attached to the upper housing either by press fit, insert molding ormolded. The center tube allows for the transfer of fluid in and out ofthe device. The rotating components of this design are the separationchamber 140, the center hub 300, and the lip seals 301. All othercomponents are held stationary during centrifugation. The rotatinglip-seal 301 interface to stationary disk 302 creates a positive andnegative pressure fluid seal.

FIG. 3C is similar to FIGS. 3A and 3B. The design shown in FIG. 3Cdiffers with a press fit bearing 303 into the lower housing 305, a onepiece lip seal 310 versus two lip seals and a flexible gasket 311 thatseals the outer edge of the sealing disk 302. The upper housing 306 isattached to the lower housing 305 and compresses gasket 311.

FIGS. 4A to 4C show various views of the top support plate 114. The topsupport plate is designed to provide structural support for theexpanding variable volume separation chamber. FIG. 4D illustrates anexploded view of the separation chamber assembly, showing the topsupport plate 114, port 124, rotating seal assembly 120, center hub 300and variable volume separation chamber 140. The rotating union generatedby the rotating seal assembly 120 allows fluid to enter and exit thevariable volume separation chamber while the chamber is rotating.

Graphical User Interface

Housing 10 includes a user interface comprising touch screen display 30,a stop button 301, a power switch, and various connectors for externalelectrical interface. The touch screen is resistive so that it willfunction if the operator is wearing gloves. The stop button is used tointerfere with automatic operation if the operator deems necessary. Allother operator interfacing is accomplished from this one screen using3-D appearance of control features and judicious use of color. Theexternal interfaces are used to upgrade software, download data, andpossibly connect to a printer.

Cartridge

FIG. 5A shows cartridge 80 that contains fluid sensor pathway 60 and thevalve assembly 70. Cartridge 80 typically comprises injection moldedpolymer. The cartridge is provided with snap-on features 82 and 84 thatpermit easy removal of the cartridge from the apparatus. (Snap tab 890is shown in greater detail in FIG. 13.) Valve housing 870 contains ports802, 804, 806, 808, and 810, each of which connect to tubing lines forthe transfer of fluid to and from the centrifuge to the 3-compartmentreservoir and/or to a syringe. Cartridge 80 also includes fluid sensorpathway 60. Tubing 62 connects port 810 to fluid sensor pathway outlet61 a. Tubing 62 is placed in the raceway of the peristaltic pump. Bloodflows in and out of fluid sensor pathway 60 through outlets 61 a and 61b.

FIGS. 6A to 6C illustrate the section views of the fluid pathwaygeometry for the fluid sensor. FIG. 6B provides a side section view ofthe fluid sensor pathway in which the fluid flow is thinned out to allowimproved detection of whole blood component layers.

Sensors

Blood components flow through the fluid sensor pathway 60 and the flowis monitored at various wavelengths. An algorithm is used to determinewhat component layer is in the fluid sensor pathway: RBC, PPP, PRP, orair. A combination of absorption and scattering causes the signal tochange. Computer software controls the intensity of the LEDs. A cutawayview of the photodiode detector placement is shown in FIG. 12.Photodiode detectors are configured to fit in pockets or openings 510and 512. These pockets are adjacent to fluid sensor pathway 60.

The system comprises three LEDs and two photodiode detectors. The firstLED is infrared, emitting light with a wavelength of 1300 nm. This LEDis matched to one of the two photodiodes. The second LED is alsoinfrared, emitting light with a wavelength of 940 nm, and the third LEDis blue, emitting light with a wavelength of 470 nm. The secondphotodiode is used to detect the light energy from the second and thirdLEDs. The second photodiode is more responsive to the 940 nm light.Accordingly, the 470 nm LED is set so that it shined directly at thedetector, while the 940 nm LED is positioned off center.

The blood path through the sensor is a rigid polycarbonate piece with anear elliptic cross section. The light shining through the piece seesthe blood interface on a flat surface. The light is directed normal tothat surface. The light emitted from each LED is electronically choppedby pulsing the LEDs on and off in sequence. The detector response isthen sampled so that any signal due to the ambient background light canbe cancelled out.

The intensity of the light emitted from the LEDs is electronicallyadjustable through a current sensing, voltage feedback amplifier. Thesignal from the detector is monitored, while the intensity of the lightis adjusted, until the signal falls within a pre-defined window. Thisprocess is accomplished automatically in software for every new caseperformed on the machine. The operator is not involved in any way withthis calibration process.

The different blood components are identified by considering theintensity of the light transmitted through the blood, as well as thederivative of the intensity as a function of time. Because the blood isflowing through the sensor while the light intensity is being sampled,the derivative of the intensity is also a function of the blood volumepassing through the sensor. The components that are identified are: (1)whole blood, (2) platelet poor plasma, (3) platelet rich plasma, (4) redblood cells, and (5) air.

Valve

The blood is separated into components in the centrifuge, which isconnected by tubing to a 4-way valve 70 contained within a disposablecartridge 80 (FIGS. 5 to 11). The disposable cartridge can be snappedonto the housing for ease of removal.

The valve is designed so that whole blood flows through the valve in its“home” position and into the centrifuge, as illustrated in FIGS. 7A and7B. The valve is then rotated to the position shown in FIG. 10A to allowthe pump to pump air through the tubing to displace the residual wholeblood volume into the centrifuge. After centrifugation of the wholeblood, the valve moves to provide a path for the platelet poor plasma(PPP) to exit the centrifuge (FIGS. 8A and 8B). The valve then moves sothat platelet rich plasma (PRP) can flow from the centrifuge into thecollection bag (FIGS. 9A and 9B). In FIGS. 10A and 10B, red blood cells(RBC) exit the centrifuge. Also in this position while red blood cellsare being pumped from the separation chamber, platelet poor plasma (PPP)can be aspirated back to be mixed with platelet rich plasma (PRP) todilute the PRP, if desired.

FIGS. 11A and 11B show the 4-way valve core 70. A stepper motor drivesthe valve core 70 to the desired locations during processing. There is apotentiometer to verify valve position based on voltage. Voltages andcurrent are measured for diagnostic purposes.

Reservoir/Collection Bag

FIG. 14 shows an embodiment of 3-compartment reservoir bag 90. The bagis flexible and preferably comprises a PVC polymer. Preferably the bagis transparent so that fluid levels can be seen easily. Whole blood isplaced into compartment 906. The blood is pumped out of this compartment(by peristaltic pump 40) and into the variable volume separation chamber140 of the centrifuge. Reservoir/collection bag 90 is shown as a3-compartment unit, and it is to be understood that this bag could beperforated for easy separation of the compartments.

After centrifugation, the blood components are sent from the centrifugethrough tubing line 410 through peristaltic pump 40 via tubing line 411into valve 70 and thus to the separation/collection bag via tubing lines412, 414, and 416. See FIG. 1. A preferred embodiment of the bag isshown in FIG. 14, wherein PPP is in compartment 902, RBC is incompartment 904, and whole blood is in compartment 906. Compartments 902and 904 are provided with outlets 912 and 914 so that the contents canbe completely and easily removed, typically by syringe. Compartment 906is provided with inlet 913. In addition, compartments 902, 904 and 906are provided with vents 924 and 926 to allow air to enter and exit.

ALTERNATE EMBODIMENTS

An alternate embodiment of this invention is illustrated in FIGS. 15 to17. This apparatus functions similarly to the apparatus described abovein FIGS. 1 to 14. FIG. 15 shows housing 1000 with display 1030. Aseparate reservoir 1096 for whole blood is provided and connected viatubing line 1046 to a common tubing line 1048 that is operably connectedvia pump loop 1040 to a pump (not shown) and to the centrifuge (notshown). Whole blood is sent to a variable volume separation chamber inthe centrifuge where it is separated (as described above for theprevious embodiment) and then the PPP and RBC components are sent to thereservoirs 1092 and 1094, respectively. PRP is collected by means ofsyringe 1098.

Fluid sensor pathway 1060 and sensors 1050 are directly in the lineto/from the centrifuge. Three pinch valves 1072, 1074, and 1076 areprovided in lines 1042, 1044, and 1046 that lead from the PPP, RBC, andWB reservoirs, respectively. These valves are operably connected to thesensors thereby automatically sending the desired fluid to the correctreservoir. For example, pinch valve 1072 is shown in FIGS. 16A and 16B.Pinch valve 1702 comprises solenoid 1700, pinch spring 1703, occludingedge of valve 1704, position sensor 1706, and housing 1710. FIG. 17illustrates a disposable portion of apparatus 1000.

The above description and the drawings are provided for the purpose ofdescribing embodiments of the invention and are not intended to limitthe scope of the invention in any way. It will be apparent to thoseskilled in the art that various modifications and variations can be madewithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A centrifuge apparatus for processing blood comprising: a bottomsupport plate; a top support plate; an axial inlet/outlet for blood tobe processed and processed components of the blood, the axialinlet/outlet being attached to the top support plate by a rotating sealassembly; a variable volume separation chamber mounted between thebottom support plate and the top support plate, the variable volumeseparation chamber being fluidly connected to the axial inlet/outlet; apump fluidly connected to the axial inlet/outlet; and a rotary driveunit attached to the bottom support plate, wherein the top holder isfixed vertically and the bottom support plate is mounted on a mechanicalactuator that maintains pressure on the variable volume separationchamber and allows the bottom support plate to move vertically, andwherein the mechanical actuator is a ball-screw actuator.
 2. Anapparatus of claim 1, wherein mechanical actuator is controlledautomatically by a processing unit.
 3. A centrifuge apparatus forprocessing blood comprising: a bottom spring-loaded support plate; a topsupport plate; an axial inlet/outlet for blood to be processed andprocessed components of the blood, the axial inlet/outlet being attachedto the top support plate by a rotating seal assembly; a variable volumeseparation chamber mounted between the bottom support plate and the topsupport plate, the variable volume separation chamber being fluidlyconnected to the axial inlet/outlet; a pump fluidly connected to theaxial inlet/outlet; and a rotary drive unit attached to the bottomsupport plate, wherein the top support plate is fixed vertically and thebottom spring-loaded support plate is mounted on springs that maintainpressure on the variable volume separation chamber and allow the bottomsupport plate to move vertically, and wherein a disposable cartridge hasbeen mounted on the apparatus, the disposable cartridge comprising aplurality of ports for receiving or dispensing blood or blood componentsand a fluid sensor pathway for displaying blood or blood components foranalysis, the cartridge being adapted to be mounted on a multi-positionvalve for directing flow between the ports and the fluid scnsor pathwaybeing adapted to be mounted adjacent to one or more sensors foranalyzing blood.
 4. An apparatus of claim 3, wherein the disposablecartridge snaps on to the apparatus.